The objective of this proposal is to develop a quantitative ultrasound technique to noninvasively assess collagen in the uterine cervix in an attempt to build a comprehensive understanding of cervical extra- cellular matrix microstructure. We anticipate that an enhanced understanding of cervical microstructural changes will lead to targeted investigation of specific remodeling processes in pregnancy that will pro- mote understanding of cervical insufficiency (that leads to preterm delivery). This in turn will allow exploration of options for novel therapeutic strategies. PUBLIC HEALTH RELEVANCE: This is a proposal to adapt new quantitative ultrasound technology to image and quantify in vivo cervical microstructure;specifically, we will target collagen because it is the primary component of the cervical extracellular matrix and, through its changes during the cervical remodeling process during gestation, is primarily responsible for cervical strength. The proposed effort involves (a) determining the sensitivity of ultrasound to the changes in collagen alignment in the cervix, (b) testing quantitative ultrasound in isotropic and anisotropic phantoms as well as ex vivo cervical tissue in order to establish imaging pa-rameters for in vivo cervical scanning, and (c) confirming through nonlinear optical imaging that we are detecting collagen in the cervix. The ability to accurately image rearrangements in collagen alignment in the cervical microstructure would inform our concept of cervical function and thus the dysfunction that leads to preterm delivery.